


In Soul, If Not In Blood

by slotumn



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Angst, Creepy Fluff, Disturbing Fluff, F/M, Family Feels, Fluff and Angst, Incest Kink, Non-Explicit Sex, Post-Timeskip | War Phase (Fire Emblem: Three Houses), Pre-Timeskip | Academy Phase (Fire Emblem: Three Houses), Pseudo-Incest, Weird Fluff, but like of the pseudo-incestuous kind, if its not actually incest then we find a way to make it incest-y, no beta we die like Glenn, that's the motto around these parts
Language: English
Status: Completed
Published: 2020-05-01
Updated: 2020-05-02
Packaged: 2021-03-02 05:08:30
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 1,855
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23949643
Author URL: https://archiveofourown.org/users/slotumn/pseuds/slotumn
Summary: He always wanted a little sibling.---While he rubbed his hands on her inner thighs over the dark fabric of her stockings, he got an idea."Lysithea.""Yes?""I'll-- buy you more cake if you call me 'big brother.'"A.K.A. Claude wants a little sister, and he also has an incest fetish. He unleashes both on Lysithea.
Relationships: Lysithea von Ordelia/Claude von Riegan
Comments: 5
Kudos: 22





	1. Big Brother

**Author's Note:**

> Special thanks to eraserheadbaby for the inspiration on this one!

He always wanted a little sibling.

A younger kid who followed him around, called him "big brother" and relied on him. Somebody he could play with and tease and protect and dote on.

He wouldn't feel so lonely, if he had somebody like that at his side. 

Of course there were other kids who had the same parent as him, but he never considered them siblings, because they humiliated him at every turn, and would never rely on him, because he was weak and a coward and didn't deserve to be the crown prince, much less be part of the same family as them. 

So he ran away to Fódlan, hoping to find something his own flesh and blood couldn't give.

And there, he found her.

\---  
\---

Everyone in Golden Deer silently agreed that she was the little sister of the group, even though they tried not to say it out loud in front of her because she hated being treated like a child and could blow them to bits with a fireball.

That was normal for a girl that age, he figured-- wanting to be seen as more mature than she really was, even though the eagerness to grow up only emphasized how young she still was.

It was so fucking adorable, and he couldn't help teasing her at every turn to see her face get flustered and indignant.

At night, he sometimes jerked off while imagining her making that same flustered face as he taught her how to feel good, like a good older brother should.

\---

"Hey, Lysithea. Do you have any siblings?"

One night at the library, it just came out of his mouth.

"...Why do you want to know?"

He shrugged. 

"Do you?"

"Not...at the moment," she replied, turning away.

That probably meant that there was a chance that her parents still might have more kids. 

So, no older siblings. 

"Would you like one?"

\---

It was pretty damn obvious that she had a crush on him, and he just couldn't help taking advantage of it. 

She complained and got all annoyed whenever he took her for little dates at the town, buying her sweets and teasing her in front of the merchants at every opportunity, but she never turned it down.

He decided to get her a big stuffed bear one day, and despite clearly liking it, she looked up at him with an unsure expression to ask,

"You...know I'm not a child, right, Claude?"

He answered her with a kiss. 

Her first, surely.

\---

On the surface, not much changed-- they still bantered back and forth as they always did, and it's not like they announced to the world that they were a thing. 

(Whatever that "thing" exactly was.)

But after their dates, they always went somewhere private to kiss.

She was short, so he usually sat down and had her straddle his lap while he licked every inch of her sweet mouth. Once they were done, faces red and all out of breath, she continued to sit on his lap while he stroked and played with her hair, braiding one of her sidelocks to match his before letting it fall loose. 

He wanted to believe that they would have done this since childhood, had they grown up together.

\---

His hands went further and further each time. It was impossible to hold back, when he saw how much she trusted him underneath her irritated retorts and glares. 

While he rubbed his hands on her inner thighs over the dark fabric of her stockings, he got an idea. 

"Lysithea."

"Yes?"

"I'll-- buy you more cake if you call me 'big brother.'"

Turns out, she didn't even need the bribe to whisper, "big brother, big brother," over and over again while grinding into his fingers, her small body shivering with sensations she never knew before.

\---

"Let's keep this a secret between us, okay?" he whispered, every time they tried something new together.

There wouldn't necessarily be negative consequences to people finding about them, of course, but close siblings all had secrets that were just between them, right? So he wanted them to have some, too.

This time, it was after she swallowed and muttered, "Tastes bad," with eyebrows scrunched and the corners of her mouth drooped.

"I know, I know. I'll get you candy after this," he stroked her cheek, "little sis."

"Do you think I can be bribed into doing anything as long as you give me sweets afterwards?"

He chuckled and kissed her forehead.

"Actually, yes."

"You're the worst," she huffed, "big brother."

Gods, he never got tired of hearing that.

\---  
\---

It hit him just how long that five years was when she appeared at the reunion as a real lady, like she always wanted to be. 

He still teased her whenever the atmosphere was less grim, but inside, he quietly forfeited the possibility of anything like their academy days happening again, even though it tore apart the heart of that lonely boy inside of him.

His house's child prodigy, his first love, his found little sister, was all grown up now. 

That meant she had to move on from the afternoons where he bought her treats and walked her around town while clasping her small hand. 

She had to move on from him. 

But he still had to let her know, one last time, that she would always be special to him, no matter what.

And when she stepped towards him and quietly whispered,

"I missed you, big brother,"

he couldn't help kissing her again, like that would forge their bloods into one.


	2. Little Sister

She didn't remember her siblings.

They all died from experiments when she was young, and her parents didn't talk of them much nor left much memorabilia to remember them, instead choosing to pour everything into her. 

Still, she strived to work hard and become the best she could be for her siblings' sakes as much as she did for her parents'-- as the sole survivor, she had an obligation to make the most out of the chances they never got, she decided. 

Some nights, when she laid on her bed, all too aware of how little time she had left, she missed them despite never having known them and wished they could be there to comfort her.

\---  
\---

He immediately got on her nerves, making fun of her for being short or a couple years younger than the others. 

But deep down, she didn't really dislike it-- bantering, being bribed with sweets, trusting and relying on him for cover on the battlefield-- even though she would never admit it out loud. There was a comfortable familiarity about the pattern, as though they've known each other for years rather than months.

She only realized what it was when Hilda and Raphael commented on it, talking about how her interactions with Claude reminded them of themselves and their siblings.

A fair assessment, she supposed-- but she was also pretty sure that those two didn't get the urge to kiss their sibling from time to time.

\---

It's not that she wanted what was already between them to stop.

But if that was the only thing he saw her as, then intuition, common sense, morals told her that she would never get the other half of what she wanted from him. 

It was supposed to be one or the other, wasn't it? Either she eternally stayed as his little sister figure, or they "moved on" to being lovers. 

Never both at the same time.

\---

Then Claude, ever so disregarding of typical conventions, started kissing her and touching her and asked her to call him "big brother" while he made her feel electrifyingly, addictively good.

Some may have said that was a warning sign, that she had to watch out for where things were going, but she knew that he would never hurt her, even as he couldn't hold back. 

Because big brothers protected little sisters.

\---  
\---

Five years later, he showed up as someone with with bigger, more important things to protect.

He didn't tease her as often, and of course there were no more afternoon dates in the town, because it was wartime, for saints' sakes.

Yet they still met at the libraries on some nights, and one evening, he told her to go to sleep in that gentle concerned voice like he used to. 

Saying that she was special to him, that there was nobody else he treated this way. (Of course there wasn't, she thought, pushing down the what-ifs about someone else taking her place.)

It was an awful, selfish idea, but if she didn't do it, her soul would never move on when she died.

"Can I sleep in your room tonight, big brother?"

Naturally, he said yes.

\---

They never went all the way back then, both because she was too small, and because it made the illusion feel more real.

Doing something that would bring a real, long-term consequence of breaking the taboo into the world was, I love you, little sis, but I don't want our hypothetical kids to suffer, he whispered, the boundaries between real and role-playing blurred to the point that he actually meant it.

Well, neither did she.

So she diligently took the herb pills in the morning after he filled her up again and again to her encouragement, moaning that she wanted her big brother's babies. 

She didn't know if she could even get pregnant after the experiments, but if she could, the pregnancy would be dangerous to herself and the child, and there was probably a high chance of the latter having birth defects. 

If, by some chance, none of those occured, the child would be still be left without a mother in their early years, and Claude would be left with an living, breathing reminder of what he lost. 

Quite ironic, really, that she achieved this much for the sake of her family, but could never start one of her own. 

But that was okay, because what she had right now-- her parents, her Golden Deer, her big brother and her love-- was enough.

\---  
\---

"I can't marry you."

He sighed, with the same expression he wore when he told her to go to sleep for the night.

"Lys...you'll always be my little sister, but it's not like we're actually related by blood, you know."

She shook her head. 

"It's not that."

The one thing he couldn't protect her from, the one secret she kept to herself instead of adding to their collection.

What drove her to cling to him became the same thing that forced her to let him go.

It was always going to end this way--

\---

\--until it didn't. 

"You didn't think I would really let you die like that, did you?" he said, tears in his eyes despite his smiling mouth. "Lysithea-- sheereen-am-- âbji."

There were so many things she wanted to ask, but instead, she kissed him until there was no air left in her lungs, and the next breath was the first one she took for herself instead of someone else. 

Surely her siblings would be proud of her for it, wherever they were.

**Author's Note:**

> [LysiClaude week twitter](https://twitter.com/LysiClaudeWeek?s=20)
> 
> [My twitter](https://twitter.com/slotumn?s=09)
> 
> Cowards: idk I see Lysithea and Claude as having more of a sibling dynamic than a romantic one  
> Me, enlightened: You fools, that's all the more reason why they should fuck


End file.
